[llvm] [EarlyCSE,TTI] Clean up temporary insts created by getOrCreateResult. (PR #134534)

[Nikita Popov via llvm-commits]

nikic wrote:

As far as I can tell, getMatchingValue/getOrCreateResult can get used either unconditionally, or for comparison against an existing value. The comparison against an existing value is of course always going to fail if new instructions are created. So I think the right way to do this would be to pass an extra flag whether creating instructions is allowed or not.

https://github.com/llvm/llvm-project/pull/134534